A method and apparatus are provided for identifying spindle imbalance in a hard disk drive. The control system is further configured to maintain the shutter in the intermediate state for a period of time, unless during this period of time high intensity light is detected, in which case the control system causes the shutter to switch to the dark state. Next provided is a peripheral lip coupled to the top edge and side edges of the base and extending upwardly therefrom. Further, the feedback signal is provided to the counter block.